Can I take bendroflumethiazide while pregnant or breastfeeding?
A plain-words look at what the NHS, the US drug label and LactMed say about bendroflumethiazide.
In short
Pregnancy: Bendroflumethiazide is not normally used in pregnancy, because other medicines are more suitable for high blood pressure.
Breastfeeding: You can take bendroflumethiazide while breastfeeding if you need to and your baby is healthy. Other medicines might be better, though, so speak to your doctor or pharmacist first and they will help you decide.
Your doctor, midwife or pharmacist can help you decide.
What this means for you
Pregnancy
- If you're pregnant or trying for a baby, ask your doctor whether bendroflumethiazide is right for you.
- They may suggest changing to another medicine for high blood pressure.
Breastfeeding
- You can take bendroflumethiazide while breastfeeding if you need to and your baby is healthy.
- Other medicines might be better, though, so speak to your doctor or pharmacist first and they will help you decide.
- The amount of bendroflumethiazide that reaches breast milk is not known, but the levels are probably low, and side effects in your baby are unlikely.
- However, taking it for a long time or at very high doses might reduce how much breast milk you make.
- Side effects in breastfed babies from medicines their mother takes are very rare, but it's important to keep an eye on your baby whenever you take a medicine while breastfeeding.
- Keep taking the medicine and carry on breastfeeding as normal until you've had advice about your baby's symptoms.
When to get help
- Contact a healthcare professional or call 111 (NHS 111 in the UK) as soon as you can if your baby is feeding less well than normal or not gaining weight as you'd expect, shows possible signs of dehydration (such as tiredness, fewer wet nappies or dark yellow pee), has diarrhoea or constipation or is vomiting (being sick), is irritable, or has a skin rash.
- For symptoms not mentioned here, or if you're worried about your baby, you can also speak to any healthcare professional or call 111.
Talk to your doctor or pharmacist
This page is educational, not advice for your own situation. Talk to your doctor, midwife or pharmacist before you start, stop or change any medicine in pregnancy or while breastfeeding.
The details: what each source says
Bendroflumethiazide in pregnancy
The NHS says
Bendroflumethiazide is not normally used in pregnancy, because other medicines are more suitable for high blood pressure.
If you're pregnant or trying for a baby, ask your doctor whether bendroflumethiazide is right for you. They may suggest changing to another medicine for high blood pressure.
In our words, from the NHS page Bendroflumethiazide (nhs.uk). Contains public sector information licensed under the Open Government Licence v3.0 (OGL v3.0). The NHS does not endorse this site.
Bendroflumethiazide while breastfeeding
The NHS says
You can take bendroflumethiazide while breastfeeding if you need to and your baby is healthy. Other medicines might be better, though, so speak to your doctor or pharmacist first and they will help you decide.
The amount of bendroflumethiazide that reaches breast milk is not known, but the levels are probably low, and side effects in your baby are unlikely. However, taking it for a long time or at very high doses might reduce how much breast milk you make.
Side effects in breastfed babies from medicines their mother takes are very rare, but it's important to keep an eye on your baby whenever you take a medicine while breastfeeding.
Contact a healthcare professional or call 111 (NHS 111 in the UK) as soon as you can if your baby is feeding less well than normal or not gaining weight as you'd expect, shows possible signs of dehydration (such as tiredness, fewer wet nappies or dark yellow pee), has diarrhoea or constipation or is vomiting (being sick), is irritable, or has a skin rash.
For symptoms not mentioned here, or if you're worried about your baby, you can also speak to any healthcare professional or call 111.
Keep taking the medicine and carry on breastfeeding as normal until you've had advice about your baby's symptoms.
In our words, from the NHS page Bendroflumethiazide (nhs.uk). Contains public sector information licensed under the Open Government Licence v3.0 (OGL v3.0). The NHS does not endorse this site.
LactMed says
No information is available on the amount of bendroflumethiazide in breastmilk. Intense diuresis with large doses of bendroflumethiazide can decrease breastmilk production, especially during the neonatal period. Shorter-acting diuretics in low doses are preferred over bendroflumethiazide.
“Summary of Use during Lactation”, LactMed record “Bendroflumethiazide” (LM27), quoted verbatim. Everything LactMed reports about Bendroflumethiazide while breastfeeding.
Sources
- NHS, Bendroflumethiazide (nhs.uk), page last reviewed 23 April 2025. Paraphrased. Contains public sector information licensed under the Open Government Licence v3.0.
- Drugs and Lactation Database (LactMed), National Institute of Child Health and Human Development (NICHD), via NCBI Bookshelf, record “Bendroflumethiazide” (LM27), bulk release of 22 September 2026. LactMed on NCBI Bookshelf. Public domain; quoted verbatim. LactMed is a registered trademark of the U.S. Department of Health and Human Services.
Sources checked 26 September 2026. How we source and check every page.
Educational summary of named sources, not medical advice.